5288f6d88d
This adds a publicly exposed experimental API for a 3D texture backend. There is a feature flag which can be checked for whether 3D textures are supported. Although we require OpenGL 1.2 which has 3D textures in core, GLES only provides them through an extension so the feature can be used to detect that. The textures can be created with one of two new API functions :- cogl_texture_3d_new_with_size and cogl_texture_3d_new_from_data There is also internally a new_from_bitmap function. new_from_data is implemented in terms of this function. The two constructors are effectively the only way to upload data to a 3D texture. It does not work to call glTexImage2D with the GL_TEXTURE_3D target so the virtual for cogl_texture_set_region does nothing. It would be possible to make cogl_texture_get_data do something sensible like returning all of the images as a single long image but this is not currently implemented and instead the virtual just always fails. We may want to add API specific to the 3D texture backend to get and set a sub region of the texture. All of those three functions can throw a GError. This will happen if the GPU does not support 3D textures or it does not support NPOTs and an NPOT size is requested. It will also fail if the FBO extension is not supported and the COGL_TEXTURE_NO_AUTO_MIPMAP flag is not given. This could be avoided by copying the code for the GL_GENERATE_MIPMAP TexParameter fallback, but in the interests of keeping the code simple this is not yet done. This adds a couple of functions to cogl-texture-driver for uploading 3D data and querying the 3D proxy texture. prep_gl_for_pixels_upload_full now also takes sets the GL_UNPACK_IMAGE_HEIGHT parameter so that 3D textures can have padding between the images. Whenever 3D texture is uploading, both the height of the images and the height of all of the data is specified (either explicitly or implicilty from the CoglBitmap) so that the image height can be deduced by dividing by the depth. |
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